The present invention relates to a mechanically amplified, multiple arm smart material actuator apparatus adapted to operate in three dimensions and incorporating a second stage assembly adapted to translate inward or outward movement of the actuating arms to linear movement of a second stage centerpiece. Mechanically amplified smart material actuators are known in the art. Such actuators, however, typically utilize one or two actuating arms and, thus, operate in essentially two dimensions. Such actuators typically require direct attachment of an actuating arm to the structure to be actuated. As a result, the attachment angle between the smart material actuator and the structure to be actuated is typically such that the direction of expansion of the smart material device is at a substantial angle to the direction of movement of the actuating arm(s). Additionally, having two or fewer actuating arms requires the expansion force of the smart material device to be distributed through at most two mechanical webs.
The present invention addresses these limitations by providing a smart material actuator with at least three actuating arms, thereby allowing for operation in three dimensions. The present invention also provides a second stage adapted to allow the movement of the actuating arms to be translated into substantially linear movement in a direction substantially along the central axis of the smart material device.
The present invention further provides a smart material actuator capable of high speed operation. Embodiments of traditional mechanically amplified smart material actuators were susceptible to failure when operated at high speeds in part due to the momentum of the actuating arms placing excess stresses on the mechanical webs. The present invention addresses that limitation by providing dampeners that prevent overextension of the actuating arms, even when the actuator assembly is operated at very high speeds.
The flexibility of the actuator according to the present invention is further enhanced through the use of interchangeable and replaceable parts. Embodiments of actuators according to the present invention allow for mountable actuating arms that permit different actuating arm lengths, materials, and angles to be utilized with a single actuator assembly. As a result, it is possible to assemble many different configurations of actuators from a common set of parts.
This application hereby incorporates by reference, in their entirety, provisional applications 61/421,504, 61/551,530, 61/452,856, 61/504,174 as well as PCT/US2010/041727, PCT/US10/041,461, PCT/US2010/47931, PCT/US2011/25299, U.S. patent application Ser. Nos. 13/203,737, 13/203,729, 13/203,743 and 13/203,345, and U.S. Patents:                U.S. Pat. No. 6,717,332;        U.S. Pat. No. 6,548,938;        U.S. Pat. No. 6,737,788;        U.S. Pat. No. 6,836,056;        U.S. Pat. No. 6,879,087;        U.S. Pat. No. 6,924,586        U.S. Pat. No. 6,870,305;        U.S. Pat. No. 6,975,061;        U.S. Pat. No. 7,564,171; and        U.S. Pat. No. 7,368,856.        